I think part of it is that creating a process is cheap in Unix-style OSs, and expensive in Windows. Windows doesn't want you to exec gcc, cpp, ld, etc. over and over again. It wants you to run an IDE that does it all in one process.
Visual Studios creates worker threads used for compiling C# that are reused for builds. This can be seen in task manager. Ran into a bug were the VS compiler would only work properly for one build and require VS to be restarted.
Visual Studios is like Windows, each version just seems to be getting worse with more bugs.
Visual Studio calls just one (msbuild) for almost all of the compilation process, perhaps half a dozen processes at most. Certainly not hundreds to thousands, as typically seen under Linux.
Using Linux in a VM compiled three times faster.
I don't know how people tolerate it.